1. Technical Field
The present invention relates to a plasma display panel that displays images using gas discharge, and more particularly, to a plasma display panel having an improved display electrode structure.
2. Related Art
In recent years, devices that use a plasma display panel (hereinafter, referred to as a “PDP”) have attracted attention as next-generation flat panel displays because of their simple manufacturing method and ease of large screen manufacturing, as compared to other flat panel displays. PDPs also have superior characteristics such as a large screen, high image quality, reduced thickness, light weight, and a wide viewing angle.
PDPs are divided into a direct current (DC) type, an alternating current (AC) type, and a hybrid type according to a discharge voltage to be applied. Further, PDPs are divided into an opposed discharge type and a surface discharge type according to a discharge structure.
The DC PDP has a structure in which all electrodes are exposed to a discharge space and electric charges travel directly between opposing electrodes. In the AC PDP, at least one electrode is coated with a dielectric and a discharge is performed with wall charges, instead of direct traveling of the electric charges between the opposing electrodes.
In the DC PDP, the electric charges travel directly between the opposing electrodes, and thus there is problem in that the electrodes are seriously damaged. For this reason, in recent years an AC PDP using AC, in particular a three-electrode surface discharge type of structure, has been generally adopted.
FIG. 1 shows such an AC three-electrode surface discharge PDP, which has a front substrate 200 and a rear substrate 300.
Formed on the rear substrate 300 are address electrodes 330 for selecting discharge cells to be turned on, a rear dielectric layer 350 in which the address electrodes 330 are buried, a barrier rib 370 for dividing discharge cells, and phosphor layers 390 that are coated on the wall surfaces of the barrier rib 370 and bottom surfaces of the discharge cells.
Provided on the front substrate 200 facing the rear substrate 300 are electrodes 220 and 230 for performing the sustain discharge of the selected discharge cells, a front dielectric layer 250 in which the electrodes 220 and 230 are buried, and a protective film 290.
In the related art PDP, a pair of electrodes 220 and 230 are provided at an upper side of each of the discharge cells. The electrodes 220 and 230 are made of transparent electrodes so as to not shield light from the discharge cells. However, the transparent electrodes have high resistance, which results in a problematic increase in discharge voltage.
For this reason, in order to reduce resistance of the transparent electrode, an electrode made of a nontransparent metal is used. In this case, however, there is a problem in that light does not pass through the metal electrode and thus an aperture ratio of the discharge cell is degraded.
In addition, the electrodes formed in such a manner are protected while being covered with the dielectric layer and the protective film. In this case, transmittance of light emitted from the discharge cells is drastically degraded due to the dielectric layer and the protective film.
Further, in the related art surface discharge type of PDP, the electrodes for generating the discharge are formed at the upper side of the discharge space, that is, an inner surface of the front substrate 200 through which light passes. Accordingly, the discharge is generated at the inner surface of the front substrate 200 and is diffused, and thus there is a problem in that luminous efficiency deteriorates.
In addition, in the related art surface discharge type of PDP, when it is used for a long time, there is a problem in that a permanent afterimage is generated due to ion sputtering of charged particles of a discharge gas to a phosphor layer by an electric field.